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Make Mobile Phones Smarter
With J2ME becoming the most common wireless app development platform, can the latest standards help you overcome its inconsistency across devices?
by Jeff Jurvis
July 2003 Issue
As mobile phones become smarter, the options for programming them are getting better (although programming for phones is not nearly as easy as it is for handhelds running Palm OS and Pocket PC). From my reckoning, there are five competing—and often cooperating—mobile phone application platforms that are making traction: Java 2 Platform, Micro Edition (J2ME, specifically "Java Technology for the Wireless Industry"); Qualcomm's Binary Runtime Environment for Wireless (BREW); Symbian OS; Openwave; and Microsoft Windows CE 3.0 for Smartphone 2002 Resources.
It's interesting to see so many options for writing wireless applications for phones, and as you might expect having so many choices complicates matters. J2ME seems to be the most popular option among handset manufacturers, and it's often found in combination with BREW, Symbian OS, and Openwave. J2ME is the most common application platform used on mobile phones today for good reason. Sun designed Java from the start to run on tight memory, processor-challenged devices, and J2ME presents a great programming model and a hospitable application environment. The problem with J2ME has been the lack of consistency across devices, which is one of the greatest challenges for Java at all levels.
The J2ME runtime environment and APIs for mobile phones are described by a specification called the Mobile Information Device Profile (MIDP) and a more specific set of specs called the Connected Limited Device Configuration (CLDC). These blueprints offer a set of functions such as user interface, network connectivity, and local data storage so that application developers know what services they can expect from the platform.
But the MIDP and the CLDC are not enough to keep mobile phone application developers from implementing competing and colliding services, hence, the establishment of a new Java Specification Request (JSR) called JSR-185, also known as Java Technology for the Wireless Industry (JTWI). As is common with JSRs, a group of contributors is defining JSR-185, including Symbian and others of the world's leading carriers and wireless software and service providers. JSR-185 requires that compliant wireless devices include MIDP 2.0 (JSR-118), CLDC 1.0 (JSR-30), and Java Wireless Messaging API (JSR-120). Optional JSRs include the Mobile Media API (JSR-135) and the draft version of CLDC 1.1 (JSR-139).
Perhaps the most valuable aspect of JSR-185 is the road map that spells out the APIs that developers can expect to see in compliant mobile devices and when those APIs will be available. The goal is to update the road map every six to nine months. Personal calendars and tasks, instant messaging and presence, location services, and security services are among JSRs under consideration for inclusion in the road map in 2003. (See "Get Small with Wireless Messaging and Mobile Media," by Daniel F. Savarese, Java Pro, March 2003.)
Something's Brewing
BREW is a product from Qualcomm, the inventors of Code Division Multiple Access (CDMA), the technology used in third- and fourth-generation wide area wireless phone and data networks. BREW is similar to J2ME and JTWI in that it provides a known execution environment and a set of APIs specific to wireless and telephony. Sun and Qualcomm believe that BREW and J2ME are complementary and are working to make J2ME an option that runs on top of BREW. At this point BREW is found on phones from Verizon and Alltel in the United States and KDF and KTTI in Asia Pacific.
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